Ankle-joint for artificial legs



A. LANG. ANKLE JOINT FOR ARTIFICIAL LEGS.

APPLICATION FILED MAR. I. I920.

Patented Jan. 11, 1921.

ARNOLD-LANG, OF, ZURICH, SWITZERLAND, ASSIGNORTO HAUSMANN' A.-G. scnrwmz.

MEDIZINAL UND SANITATSGESCHAFT LAND.

1 ,365, 1 77. p p I Application filed v.ilifarch 1,

T 0 all whom it may concern:

Be it known that I, ARNOLD LANG, a citizen of the Republic of Germany, residing atZurich, Minervastrasse 12, have invented certain new and useful Improvements in Ankle-Joints for Artificial Legs; and I do hereby declare the following to be a clear, full, and exact description of the invention,

such as will enable others skilledin the art to Which it appertains to, make and use the, same, reference being had to the accompanying drawing,a'nd to letters or figures of reference marked thereon, which form a part of this specification.

All the hitherto known ankle-joints are provided with two springs and one pivot.

The springs act in the resting position with the same tension or pressure in order to hold the foot-part in that position to the leg-part which corresponds to the resting position. In this arrangement the springs are continuously and excessively strained and a balancing effect of the leg-part on the foot-part is unavoidable. The lift of the springs is very great so that the springs will soon lose their elastic power.

- The present invention relates to an anklejoint for artificial legs in which the above mentioned disadvantages are avoided. 1 According to this invention two supports are provided in the articulated joint between the foot-part and the leg-part, which parts are resiliently connected by a spring in such a way that in the resting position the leg-part is supported on the foot-part by means of the two supports, and on moving the legpart relatively against the foot-part one of the supports is acting as a pivot while the other is lifted off its bearing surface in a turning motion around said pivot as fulcrum, which movement increases at the same time the tension of the spring.

The drawing shows an example of carrying this invention into effect and it is:

Figure 1 a side view wherein some parts are shown in section,

Fig. 2 a cross-section along line A-B of Fi it the bottom of a recess 1 of a foot-part 2 a metal plate 3 is fixed. On this metal plate 3 a wooden block 4 is mounted which is held in position on the metal plate 3 by means of lateral ears 5 of the metal plate Specification of Letters latent.

s1. GAZLLEN, on ST. GAL EN, swm'znn- ANKLE-JOINT FOR ARTIFICIAL LEGS.

Patented Jan. 11, 1921.

1920. Serial No. 362,431.

3 and by a plate 6 which is bent like a stirrup.v i

fiatypiece 7: project with the shanks 8, 9 through a slot 10 of the stirrup 6 into aslot 11 of the wooden block 4. At the free end of each of these shanksS, 9 a'bolt 12 is provided, which bolts rest in notches 13 of the wooden block 4. Between the shanks 8, 9

a cylindrical spiralspring 14 is arran ed, 'WhlCh is fastened atone end to the flat plece 7 and at the other end to a screw bolt 15. Said screw bolt 15 projects through the plate 6, the wooden block 4, the metal plate 3 and through the part 2 of the foot-part, which carries the metal-plate 3, and thereby the whole joint-device and the bolt 15 is adapted to be screwed down by means of a screw nut 16 for the purpose of regulating the tension of the cylindrical spiral spring 14.

The spring 14 effects a pull on the shanks 8, 9 of the flat piece 7 and presses in this way the bolts 12 onto the bottom of the I 7 denotes a stirrup like flat piece to which I the leg-part in the drawing is fixed. The

notches 18, whereby, when the leg-part and foot-part are in a resting position, the former is supported by the latter in two points. If, however, the leg-part is moved for instance toward the front, said part executes a turning motion around the bolt 12 provided on the shank 8 as pivot. Hereby the bolt 12 provided on the shank 9 is lifted out of the notch 13 and the spring 14 is tightened. If, on the other hand, the legpart is moved toward the rear, it turns around the bolt 12 of the shank 9 as pivot whereby the bolt 12 of the shank 8 is lifted out of the notch 13 and the spring 14 is tightened.

By means of said arrangement of two supports and only one, spring placed between them, a good seating of the leg-part toward the foot-part is obtained in the resting position, and the tension of the spring is reduced to a minimum, as the. travel of the spring is in this case much smaller than if the lower pivot to which the spring is connected lies beyond the turning point as is the case with the hitherto known anklejoints. Therefore, a spring-arranged in acbacklash, which is caused in the known ankle-joints when the springs get weak, is avoided.

I claim: a

1. An ankle joint for artificial legs, comprising a portion for attachment to the leg and a portion for attachment to the foot, two pivot pins interposed between and connected to one of said portions and support-.

ing the leg portion on the foot portion, and a resilient tension member to press the parts together against said pivots.

2. An ankle joint "for artificial legs, comprising a leg plate and a foot portion, a pair of spaced pins on the leg plate, said foot portion having notches in which said pins seat, and a spring between the leg plate and foot portion to hold said pins in the notches.

3. An ankle joint for artificial legs, comprising a leg plate, a foot portion comprising a block having a pair of horizontally spaced notches therein, pins-in said plate seating in said notches, means for holding i said block to the artificial foot and simultaneously preventing the pins from leaving the notches, and a spring connected to the leg plate and foot portion to yieldingly hold the pins in their notches.

a. In an ankle joint for artificial legs, a forked leg plate for fastening to the lower end of the artificial leg, a pin in each end of said fork, a block to be fastened to the artificial foot and having two notches in its top to receive said pins, a strap to hold said block and covering said notches, a bolt arranged to pass through the instep of the artificial foot and passing through said block and strap between the ends of the forked leg plate, and a coil spring connected at one end to said plate and at the other end to said bolt, said bolt serving as means for regulating the tension of said spring.

In testimony that I claim the foregoing a my invention, I have signed my name.

ARNOLD LANG. 

